When repairing disc brakes and replacing brake pads it is generally preferred to cut the friction surface of the rotor to create a smooth finish, eliminating scratches and grooves which impair braking efficiency, and true the rotor. The rotor is normally cut by placing the rotor on a brake rotor lathe, which turns the rotor at high speeds, and running a cutting tool across the friction surface of the rotor to create an even cut with very close tolerances. Similarly, U.S. Pat. No. 4,226,146 refers to a lathe which can be used to cut a rotor without removing the rotor from the vehicle.
After the brake surface of the rotor is cut it is desirable to create a non-directional finish on the friction surface to improve friction between the brake pad and the surface. Also, it is at times preferable to place a finish on the friction surfaces of a rotor when it has not been cut to improve braking.
Generally, a finish is placed on the friction surface by hand sanding the surface with a fine or medium grit sand or emery paper or using a mechanical sander about the circular rotor friction surface. The procedure must be carried out on each side of the rotor separately.
An example of a mechanical grinder for use with brake rotors is found in U.S. Pat. No. 3,500,589. U.S. Pat. No. 3,500,589 refers to a device mounted to a brake lathe that is brought into engagement with the two opposed surfaces separately by manually removing the grinding disc from one side of the mount and replacing it on the other side of the mount to finish the other surface. Also, moving the tool carriage is required to engage the surfaces. This, however, beyond requiring time consuming steps, leaves the mount in place even when not in use, interfering with the use of the lathe for cutting the rotor.
Therefore, it is an object of the present invention to provide a quick and efficient non-directional finish to the friction surface on both sides of a brake rotor, after cutting, while the rotor is spinning either on a brake rotor lathe or on the vehicle.
It is a further object of this invention to provide such a finish with a device that does not require an external power source.
It is yet another object of the present invention to provide a device for creating a non-directional finish on a brake rotor which is hand held and can be used on rotors spinning either on a rotor lathe or on the vehicle and can be easily stored or transported.
It is another object of the invention to provide a rotor finishing device with replaceable finishing surfaces which needs little if any maintenance.